Dell 2135cn Service Manual page 672

Chapter 3 Removal and Replacement Procedures (RRPs)
4) Mate the tab of the STOPPER PIVOT
with the notch of the DRIVE ASSY MAIN,
attach the STOPPER PIVOT to the PIVOT
TRANS L.
5) Rotate the STOPPER PIVOT to the left,
secure the STOPPER PIVOT to the
DRIVE ASSY MAIN frame.
Go to the next replacement step:
Replacement 14 COVER ASSY FRONT (PL10.2.1)
3 - 170
Version 
2008.02.01